This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Food allergies affect 6% of infants and children, and milk, egg, soy, wheat, peanut, and fish account for >90% of all food allergies in this age group (1, 2). The majority of children outgrow their allergies but the exact mechanisms by which tolerance to foods is achieved are unknown. The only currently available therapy is avoidance of the offending food. It is believed that strict avoidance not only prevents acute food-allergic reactions but also shortens the time to achieve the development of tolerance. However, in our clinical practice it appeared that some children lost their food hypersensitivity in spite of frequent ingestions of small amounts of processed forms (e. g. baked products) of the offending food whereas other children had persistent food allergies despite truly strict elimination of the food allergen from the diet. Therefore, we intend to investigate whether ingestion of small amounts of processed milk protein might be permitted without compromising the chances for ultimately outgrowing the food hypersensitivity nor prolonging the time needed to achieve clinical tolerance.